c++ 79,80,81

79

#include <stdio.h>void main(){    /* sizeof()是保留字，它的作用是求某类型或某变量类型的字节数, */    /* 括号中可以是类型保留字或变量。*/    /*int型在不同的机器，不同的编译器中的字节数不一样,*/    /*一般来说在TC2.0编译器中字节数为2,在VC编译器中字节数为4 */    printf("The bytes of the variables are:\n");    printf("int:%d bytes\n",sizeof(int));    /* char型的字节数为1 */    printf("char:%d byte\n",sizeof(char));    /* short型的字节数为2 */    printf("short:%d bytes\n",sizeof(short));    /* long型的字节数为4 */    printf("long:%d bytes\n",sizeof(long));    /* float型的字节数为4 */    printf("float:%d bytes\n",sizeof(float));    /* double型的字节数为8 */    printf("double:%d bytes\n",sizeof(double));    /* long double型的字节数为8或10或12 */    printf("long double:%d bytes\n",sizeof(long double));    getchar();}

80

#include <stdio.h>main(){char ch,nch;/* */int count;/* */int k;/* */printf("Please input a string with a # in the end.\n");scanf("%c",&ch);/* */while(ch != '#')/* */{if(ch >= '0' && ch <= '9'){/* */count = ch-'0'+1;/* */scanf("%c",&nch);/* */for(k=0;k<count;k++)/* */printf("%c",nch);}elseprintf("%c",ch);/* */printf(" ");/* */scanf("%c",&ch);/* */}printf("#\n");/* */}

81

#include <stdio.h>main(){int a=5,b,c,i=10;b=a++;c=++b;printf("a = %d, b = %d, c = %d\n",a,b,c);printf("i,i++,i++ = %d,%d,%d\n",i,i++,i++);printf("%d\n",++i);printf("%d\n",--i);printf("%d\n",i++);printf("%d\n",i--);printf("%d\n",-i++);printf("%d\n",-i--);getchar();}