if statement analysis
if statement is used to select the execution statement according to the condition
else cannot stand alone and always matches its nearest if
You can connect other if statements after the else statement
if（condition）
{
// statement 1
}
else
{
// statement 2
}
Points to note about zero value comparison in if statements
bool variables should appear directly in the condition, do not compare
When comparing a variable with a value of 0, the value of 0 should appear to the left of the comparison symbol
float type variables cannot be directly compared with 0 value, you need to define the precision
bool b = TRUE;
if （b）
{
// statement1
}
else
{
// statement 2
}
int i = 0;
if (0 == i)
{
// statement 1
}
else
{
// statement 2
}
#define EPSION 0.000001
float f = 0.0;
if ((-EPSION <= f) && (f <=-EPSION ))
{
// statement 1
}
else
{
// statement 2
}
swith statement analysis
The switch statement corresponds to a single condition with multiple branches
The case statement branch must have a break, otherwise it will cause branch overlap
The default statement is necessary to deal with special cases
switch(expression)
{
case CONST_1:
// code block
break;
case CONST_2:
// code block
break;
default:
// code block
}
The value in the case statement can only be integer or character
order of case statements
Arrange the sentences in alphabetical or numerical order
Put the normal situation in the front, and the abnormal situation in the back
The default statement is only used to deal with the real default situation
