C 例判断输入字符种类 ch4 3 c*/ #include <stdio. h> maino char c printf("enter a character: c=getchar if(c<0x20) printf( "The character is a control characterIn") else if(c>=o'&&c<=9) printf( The character is a digitin") else if(c>='A'&&c<=Z) printf(" The character is a capital letterIn") else if(c>='a'&&c<='z) printf(" The character is a lower letter in else printf("The character is other characterIn") 运行: Enter a character:F1 The character is other character
/*ch4_3.c*/ #include <stdio.h> main() { char c; printf("Enter a character:"); c=getchar(); if(c<0x20) printf("The character is a control character\n"); else if(c>='0'&&c<='9') printf("The character is a digit\n"); else if(c>='A'&&c<='Z') printf("The character is a capital letter\n"); else if(c>='a'&&c<='z') printf("The character is a lower letter\n"); else printf("The character is other character\n"); } 例 判断输入字符种类 运行：Enter a character： The character is a control character 运行：Enter a character：8 The character is a digit 运行： Enter a character： D The character is a capital letter 运行： Enter a character： h The character is a lower letter 运行： Enter a character：F1 The character is other character
ⅱf语旬嵌套 ●一般形式: if(expr1) if (expr 1) if(expr2) 内嵌if if(expr 2) statement1 statement 内嵌if else else statement statement2 if (expr1) statement 1 if(expr1) if(expr2) statement else if(expr3) statement2内嵌if statement内嵌r if(expr3) statement else else statement statement4/内嵌if
vif语句嵌套： l一般形式： if (expr1) if (expr2) statement1 else statement2 else if(expr3) statement3 else statement4 内嵌if 内嵌if if (expr1) if (expr2) statement1 else statement2 内嵌if if (expr1) if (expr2) statement1 else statement3 内嵌if if (expr1) statement1 else if(expr3) statement3 else statement4 内嵌if
例输入两数并判断其大小关系c Ch4 #include <stdio.h> maine Int x,y, 运行: Enter integer x,y:12,23 printf( "Enter integer x, y: " X<Y scanf( %od, %od", &x, &y) Enter integer x, y: 12,. Y if(xl=y) Enter integer x,y: 12, 12I if(x>y) printf("X>Yn") X=Y else printf("XYn") else printf("X=Yn")
例 输入两数并判断其大小关系 /*ch4_4.c*/ #include <stdio.h> main() { int x,y; printf("Enter integer x,y:"); scanf("%d,%d" ,&x,&y); if(x!=y) if(x>y) printf("X>Y\n"); else printf("X<Y\n"); else printf("X==Y\n"); } 运行：Enter integer x,y:12,23 X<Y Enter integer x,y:12,6 X>Y Enter integer x,y:12,12 X==Y
●if~else配对原则:缺省{}时,else总是和它 上面离它最近的未配对的ⅱf配对 if( f( if( else se else
lif ~ else 配对原则：缺省{ }时，else总是和它 上面离它最近的未配对的if配对 if(……) if(……) if(……) else…... else…... else…
if (a==b) if(b==c) printf(a==b==c”); Ise printf( a!=b”); 修改:if(a=b) if(b==c) printf( a==b==c”) else printf( a!=b”) 实现if~else正确配对方法:加{}
例： if (a==b) if(b==c) printf(“a==b==c”); else printf(“a!=b”); 修改： if (a==b) { if(b==c) printf(“a==b==c”); } else printf(“a!=b”); 实现if ~ else 正确配对方法：加{ }