c语言第一章例子

C语言教学

#include <stdio.h> int main( ) { printf("123\"456\"789\n"); //转义符\”，\n printf("123\b456\t789\n\n"); //转义符\b，\t，\n printf("142\t\\142\n"); //转义符\t，\\，\n printf("\142\t\x62\n"); //转义符\142，\t，\x62，\n return 0; } #include <stdio.h> int main() { int num; //定义整型变量 num char sex; //定义字符类型变量 sex float score; //定义浮点型变量 score double average; //定义浮点型变量 average num=100; sex='m'; score=85.0f; average=92.5; printf("num=%d\n",num); //输出 printf("sex=%c\n",sex); printf("score=%f\n",score); printf("average=%f\n",average); return 0; } #include <stdio.h> int main( ) { int num=3; printf("变量 num 的值是：%d\n", num); //输出 num 的值 printf("变量 num 的地址是：%d\n",&num); //输出&num 的值 return 0; } #include <stdio.h> int main() { printf("数据类型 \t字节\n"); printf("--------- \t-----\n"); printf("char \t\t %d\n", sizeof(char)); printf("short int \t %d\n", sizeof(short)); printf("int \t\t %d\n", sizeof(int)); printf("long int \t %d\n", sizeof(long)); printf("float \t\t %d\n", sizeof(float)); printf("double \t\t %d\n", sizeof(double)); printf("long double \t %d\n", sizeof(long double)); return 0; } #include <stdio.h> void main() { int li_num,zhao_num,li_total,zhao_total; char mychar; mychar='a'; li_num=10; zhao_num=12; li_total=li_num *15; zhao_total= zhao_num*15; printf("li_total=%d \n",li_total); printf("zhao_total= %d,mychar=%c\n", zhao_total,mychar); } #include <stdio.h> #define PI 3.14 int main() { int r=2; //定义圆的半径为 2 float c,s; //定义圆的周长和面积 c=2*PI*r; //计算圆的周长 s=PI*r*r; //计算圆的面积 printf("PI 的值是%f\n",PI); //输出 printf("圆的周长是%f\n",c); printf("圆的面积是%f\n",s); return 0; } #include <stdio.h> int main( ){ printf ( "yes sir" );return 0;} #include <stdio.h> int main() {printf("this is a city\n"); printf(" beautiful lady\n"); printf( "please,let me see!"); return 0; } #include <stdio.h> void main() { float a,b ; a = 126567678678 ; b = a + 20 ; printf("%f\n",b);} #include <stdio.h> int main() { double c; //定义华氏温度变量 double f; //定义摄氏温度变量 f=100.0; //摄氏温度赋值为 100 c=5.0/9.0*(f-32.0); //计算华氏温度 printf("摄氏温度 100=华氏温度%f\n\n",c); c=100.0; //华氏温度赋值为 100 f=9.0/5.0*c+32.0; //计算摄氏温度 printf("华氏温度 100=摄氏温度%f\n",f); return 0; }