Re: [問題]C++ 九九乘法表如何用if來寫呢??

看板C_and_CPP作者lungswu (宅爸爸)時間16年前 (2010/02/01 18:36)推噓5(5推 0噓 9→)

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/* 恕刪全文... 我認為 do-while, while-do, for迴圈某種程度上是由 if 判斷式加上 goto 組合而成(前板有推文中也有提到) 之間可以互用，這邊獻個醜，若有不對觀念請鞭小力點謝謝.... 以下的source cide中將USING_LOOP的定義改成1~4，再用 gcc -E 就可以看出不同的寫法，但一樣的結果 :) <P.S> 抱歉，我不會用C++，改成C .... */ #define USING_LOOP 4 #define LOOP_FOR 1 #define LOOP_DO_WHILE 2 #define LOOP_WHILE_DO 3 #define LOOP_IF_GOTO 4 #if (USING_LOOP == LOOP_FOR) #define LOOP_BEGIN(F, Begin, Stop, Step) \ for(Begin; Stop; Step) { #define LOOP_END(F, Begin, Stop, Step) \ } #elif (USING_LOOP == LOOP_DO_WHILE) #define LOOP_BEGIN(F, Begin, stop, step) \ Begin; do { #define LOOP_END(F, Begin, Stop, Step) \ Step; } while(Stop); #elif (USING_LOOP == LOOP_WHILE_DO) #define LOOP_BEGIN(F, Begin, Stop, Step) \ Begin; while(Stop) { #define LOOP_END(F, Begin, Stop, Step) \ Step; } #elif (USING_LOOP == LOOP_IF_GOTO) #define LOOP_BEGIN(F, Begin, Stop, Step) \ Begin; loop_begin_##F: #define LOOP_END(F, Begin, Stop, Step) \ Step; if (Stop) {goto loop_begin_##F;} #endif int main(int argc, char *argv[]) { int i , j; int sum; LOOP_BEGIN(a, i = 1, i <= 9, i++) { LOOP_BEGIN(b, j = 1, j <= i, j++) { sum=i*j; printf("%d*%d=%d ", j, i, sum); } LOOP_END(b, j = 1, j <= i, j++) printf("\n"); } LOOP_END(a, i = 1, i <= 9, i++) return 0; } -- ※ 發信站: 批踢踢實業坊(ptt.cc) ◆ From: 114.136.210.73

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adrianshum

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