[已解决]for循环嵌套

顾西凉

求助， 9*9乘法表把我搞懵了  看不懂代码了  能帮我解释一下吗 还有后面的k代表的是什么？
另外写循环嵌套有什么技巧吗能保证理清思路   谢谢大佬了

最佳答案

月排行榜 / 总排行榜

bin554385863

2019-10-22 23:15:27

#include <iostream>
int main(int argc, char const *argv[])
{
    for (size_t i = 1; i < 10; i++)//控制行
    {
        for (size_t j = 1; j <= i; j++)//控制列
        {
            printf("%dX%d=%2d  ", j, i, i * j);
        }
        printf("\n");//内层每完成i次循环,外层打印一次换行
    }
    return 0;
}

---------------------------------------------------------------------------------------------------------------
Microsoft Windows [版本 10.0.16299.1087]
(c) 2017 Microsoft Corporation。保留所有权利。

E:\Users\86184\Documents\Code>c:\Users\86184\.vscode\extensions\ms-vscode.cpptools-0.26.0\debugAdapters\bin\WindowsDebugLauncher.exe --stdin=Microsoft-MIEngine-In-5kosn4ur.fx4 --stdout=Microsoft-MIEngine-Out-umo3qoeh.knl --stderr=Microsoft-MIEngine-Error-kyifrxzn.yov --pid=Microsoft-MIEngine-Pid-dw0aq1lg.2ni "--dbgExe=E:\My Program\MinGW\bin\gdb.exe" --interpreter=mi
1X1= 1
1X2= 2  2X2= 4
1X3= 3  2X3= 6  3X3= 9
1X4= 4  2X4= 8  3X4=12  4X4=16
1X5= 5  2X5=10  3X5=15  4X5=20  5X5=25
1X6= 6  2X6=12  3X6=18  4X6=24  5X6=30  6X6=36
1X7= 7  2X7=14  3X7=21  4X7=28  5X7=35  6X7=42  7X7=49
1X8= 8  2X8=16  3X8=24  4X8=32  5X8=40  6X8=48  7X8=56  8X8=64
1X9= 9  2X9=18  3X9=27  4X9=36  5X9=45  6X9=54  7X9=63  8X9=72  9X9=81

E:\Users\86184\Documents\Code>
=======================================================
倒序

#include <iostream>
int main(int argc, char const *argv[])
{
    for (size_t i = 9; i >= 1; i--) //控制行
    {
        for (size_t j = 1; j <= i; j++) //控制列
        {
            printf("%dX%d=%2d  ", j, i, i * j);
        }
        printf("\n"); //内层每完成i次循环,外层打印一次换行
    }
    return 0;
}

-----------------------------------------------------------------------------------------------------------------------------
Microsoft Windows [版本 10.0.16299.1087]
(c) 2017 Microsoft Corporation。保留所有权利。

E:\Users\86184\Documents\Code>c:\Users\86184\.vscode\extensions\ms-vscode.cpptools-0.26.0\debugAdapters\bin\WindowsDebugLauncher.exe --stdin=Microsoft-MIEngine-In-s1vqqpin.jpr --stdout=Microsoft-MIEngine-Out-qusqcgs1.ind --stderr=Microsoft-MIEngine-Error-awammhke.fmu --pid=Microsoft-MIEngine-Pid-lyi5ydnv.4hm "--dbgExe=E:\My Program\MinGW\bin\gdb.exe" --interpreter=mi
1X9= 9  2X9=18  3X9=27  4X9=36  5X9=45  6X9=54  7X9=63  8X9=72  9X9=81
1X8= 8  2X8=16  3X8=24  4X8=32  5X8=40  6X8=48  7X8=56  8X8=64
1X7= 7  2X7=14  3X7=21  4X7=28  5X7=35  6X7=42  7X7=49
1X6= 6  2X6=12  3X6=18  4X6=24  5X6=30  6X6=36
1X5= 5  2X5=10  3X5=15  4X5=20  5X5=25
1X4= 4  2X4= 8  3X4=12  4X4=16
1X3= 3  2X3= 6  3X3= 9
1X2= 2  2X2= 4
1X1= 1
E:\Users\86184\Documents\Code>

跳转到最佳答案楼层

ba21

跟着代码一步一步走，你不走流程；解释不来，解释了你也不懂。

bin554385863

#include <iostream>
int main(int argc, char const *argv[])
{
    for (size_t i = 1; i < 10; i++)//控制行
    {
        for (size_t j = 1; j <= i; j++)//控制列
        {
            printf("%dX%d=%2d  ", j, i, i * j);
        }
        printf("\n");//内层每完成i次循环,外层打印一次换行
    }
    return 0;
}

---------------------------------------------------------------------------------------------------------------
Microsoft Windows [版本 10.0.16299.1087]
(c) 2017 Microsoft Corporation。保留所有权利。

E:\Users\86184\Documents\Code>c:\Users\86184\.vscode\extensions\ms-vscode.cpptools-0.26.0\debugAdapters\bin\WindowsDebugLauncher.exe --stdin=Microsoft-MIEngine-In-5kosn4ur.fx4 --stdout=Microsoft-MIEngine-Out-umo3qoeh.knl --stderr=Microsoft-MIEngine-Error-kyifrxzn.yov --pid=Microsoft-MIEngine-Pid-dw0aq1lg.2ni "--dbgExe=E:\My Program\MinGW\bin\gdb.exe" --interpreter=mi
1X1= 1
1X2= 2  2X2= 4
1X3= 3  2X3= 6  3X3= 9
1X4= 4  2X4= 8  3X4=12  4X4=16
1X5= 5  2X5=10  3X5=15  4X5=20  5X5=25
1X6= 6  2X6=12  3X6=18  4X6=24  5X6=30  6X6=36
1X7= 7  2X7=14  3X7=21  4X7=28  5X7=35  6X7=42  7X7=49
1X8= 8  2X8=16  3X8=24  4X8=32  5X8=40  6X8=48  7X8=56  8X8=64
1X9= 9  2X9=18  3X9=27  4X9=36  5X9=45  6X9=54  7X9=63  8X9=72  9X9=81

E:\Users\86184\Documents\Code>
=======================================================
倒序

#include <iostream>
int main(int argc, char const *argv[])
{
    for (size_t i = 9; i >= 1; i--) //控制行
    {
        for (size_t j = 1; j <= i; j++) //控制列
        {
            printf("%dX%d=%2d  ", j, i, i * j);
        }
        printf("\n"); //内层每完成i次循环,外层打印一次换行
    }
    return 0;
}

-----------------------------------------------------------------------------------------------------------------------------
Microsoft Windows [版本 10.0.16299.1087]
(c) 2017 Microsoft Corporation。保留所有权利。

E:\Users\86184\Documents\Code>c:\Users\86184\.vscode\extensions\ms-vscode.cpptools-0.26.0\debugAdapters\bin\WindowsDebugLauncher.exe --stdin=Microsoft-MIEngine-In-s1vqqpin.jpr --stdout=Microsoft-MIEngine-Out-qusqcgs1.ind --stderr=Microsoft-MIEngine-Error-awammhke.fmu --pid=Microsoft-MIEngine-Pid-lyi5ydnv.4hm "--dbgExe=E:\My Program\MinGW\bin\gdb.exe" --interpreter=mi
1X9= 9  2X9=18  3X9=27  4X9=36  5X9=45  6X9=54  7X9=63  8X9=72  9X9=81
1X8= 8  2X8=16  3X8=24  4X8=32  5X8=40  6X8=48  7X8=56  8X8=64
1X7= 7  2X7=14  3X7=21  4X7=28  5X7=35  6X7=42  7X7=49
1X6= 6  2X6=12  3X6=18  4X6=24  5X6=30  6X6=36
1X5= 5  2X5=10  3X5=15  4X5=20  5X5=25
1X4= 4  2X4= 8  3X4=12  4X4=16
1X3= 3  2X3= 6  3X3= 9
1X2= 2  2X2= 4
1X1= 1
E:\Users\86184\Documents\Code>